How fast do you drive on the freeway?

Question

Studies have shown that for every extra 10 mph you drive on the freeway, you lose approximately 4 mpg of fuel efficiency.

For example, if you drive 75 mph in a standard sedan as opposed to 65 mph, your fuel efficiency will drop from 30 mpg to 26 mpg.

http://finance.yahoo.com/family-home/article/104752/Slow-Down-a-Lttle-Save-a-Lot-of-Gas

If you travel 30 miles, that extra 10 mph of speed will save you about 3.5 minutes, and you'll waste an extra 0.15 gallons of gas (approximately 50 cents worth), not to mention the extra emissions from that wasted gas. Is it worth 50 cents to save 3.5 minutes?

How fast do you drive on the freeway, and why?

Answer 1

I usually hang at 60-65.  I have no need to go faster for the 15 or so miles I drive on it daily and could give a flying f**k what all the speed demons think.  If people would actually do the math and figure out that they're saving a grand total of a minute and 37 seconds by driving like a complete moron on their way to work, they'd probably slow down.

Answer 2

75-80 on freeways. 4mpg drop is probably correct for highly efficient Camry, but I doubt it will translate into similar savings across the board.

Why? I just try not to clog the roads with my car.

Answer 3

On the freeway in town, I drive at about the same speed as everyone else.  I do this for safety reasons.  Cross country, I usually drive about 80-90mph.  I do this to save time.  Time is money, so yes, it is worth the marginal extra fuel cost, at least for me.

I doubt your numbers on fuel efficiency, however, I have not seen this much drop in my car.  Exactly what studies can you quote to support the -4mpg/10mph number.

Answer 4

lol, Honestly, depending on driving/road conditions, on a freeway (for me, and Insterstate usually) I drive as fast as I can that doesn't get me pulled over (sorry, places to be, places to see... but please allow me to explain...).

A state trooper informed me that, in NY State anyway (65 mph speed limit here), they pay attention when you're driving over 75 during the day, and over 72 during the evening or in weather which forces you to have your lights on (in NYS, you must always have your lights on if you are using wipers).  So I tend to drive right around 70-72 at all times.  Although, if traffic is moving at a constant, either faster or slower, I will go with the flow of traffic simply to be more on the safe side.

To compensate for my slightly faster on the freeway driving (I drive more normal elsewhere, right at speed limit usually in-town), I chose a job a few minutes from my home, I live a few minutes from everything in fact, the mall, grocery stores, service stations, you name it.  However, weather permitted and once my motorcycle is running again, I will be using my bike to get to work and back (no car can beat that deal).  

Interesting question Dana... sort of tricky, you trying to make us feel guilty about raising our estimated fuel economy by 3-4 mpg because of our Freeway habits?  lol, just kidding, every little bit counts.   But seriously, does anyone do less or just the speed limit?  I tend to think those people are more dangerous, for one, they're frozen in their lanes and can never seem to move out of the way, they hit their brakes, etc.  When it comes to the freeway... best to go with the flow.

Saving money and reducing your carbon footprint however, anywhere you can, is a good idea, but in this example, better is to get a more fuel efficient vehicle, try to carpool whenever possible, get a motorbike, or a regular bike (for short trips), use public transportation (if it is available), try to not depend so much on your AC all the time, get a tune-up... seriously, i.e. was having sort of sluggish acceleration during certain cruising and acceleration points, I found out I had a faulty sensor, a common failed sensor in Fords, they said it would be about $185 to order and replace... instead, all I did was replace the simple DPFE sensor I bought NEW on eBay for $35, installed it myself in 30 seconds and it actually improved my EFE (estimated fuel efficiency) about 5 mpg (over 15 percent)!  

So I recommend that you make sure all your sensors are working properly, and replace air filters regularly (simply by replacing a dirty air filter can also improve performance and overall fuel efficiency by as much as 10 percent) and keep you tires properly inflated (improves safety, and can improve EFE by 5 percent)...

Thanks for the post, made me think a little.

PS - Some other things to consider...

Answer 5

I usually go the speed limit. What I don't like is the drivers that don't go the speed limit and mess up the flow of traffic.

Answer 6

I never, EVER, go more than 5 miles above the speed limit.

People flying down the highway are homocidal maniacs.

And a$sholes.

And the people saying they "go however fast everybody else is going" just KILL me.

"Oh, if he jumps off of a bridge are you going to do it, too?"

Remember when our parents used to tell us that?

Why do I drive the speed limit or at the most, five miles above it?

Because any highway patrolman (or Emergency Medical Technician) will tell you that the fatalities go up with every additional mile per hour you bullet your car down the freeway. Driving too fast is foolhardy and irresponsible. Heck, it's downright antisocial.

My life is worth more than that.

And also, I don't want the speeding ticket and the additional higher insurance premium you get when you do get that speeding ticket.

And also,

BECAUSE IT 'S THE LAW.

****************************

OH! Duh - and of course because it is the environmentally responsible thing to do!

Answer 7

I drive according to road conditions. On a clear dry road, I set the cruise control to the posted limit.  If someone wants to go faster, I give them room to pass when the road is clear.  It is satisfying to pass the same driver a few miles down the road explaining his/her haste to a peace officer.  In the winter, my highway speed ranges from the speed limit in good conditions to less than 30 kph in poor conditions.  I have taken 3.5 hours in the winter for a trip that takes 1.25 hours in the summer.  Most drivers slow to a crawl in bad conditions, but there are always a few @*&%$&#'s that want to drive over the speed limit on glare ice in a blizzard putting the lives of everyone around them at risk.

Answer 8

i try to leave extra time for journeys and stick to 'truck speed' (55 - 60 mph here) but i do find myself creeping up to 70.

i do love to use momentum, and plan well ahea

to avoid ever having to brake.

Answer 9

I drive about 70.  (I spend too much time on Yahoo Answers, so I have to make up for lost time.)  I rarely drive less than 90 miles on the freeway, and I often drive 300-650 miles, so a 15% time savings is significant.  

It is frustrating that there aren't far more roadside rest areas so I could get off the road earlier rather than having to rush to get to the next one before continued driving gets too late and dangerous.  I've hit multiple deer in the past few years.  If I had been driving 15% slower (15% more time on the road, driving even later, less alert) I might have hit more.  (No, I couldn't have prevented the 50MPH one any better than the 60MPH one, and I risk a rollover death trying to evade anything that hops onto the road at either of those speeds.)

Automakers could easily make a vehicle that would meet my needs and get 4MPH better mileage.  I'm looking right now and I can't find such a vehicle (Subarus, Honda Elements are too short).  I'll probably end up with another overpowered SUV.  It's frustrating, particularly with gas heading for $4+ per gallon, and doubling in price every 6-8 years.

Answer 10

I drive between 65-80mph on the freeway in Southern California, when you can actually drive that fast.  Most days I am excited to drive 10mph on the 405S.  When it is clear, I use the gentle hill areas to either speed up or slow down.  I don't like getting less than 46mpg in my little black Prius.

Answer 11

<<How fast do you drive on the freeway? <<

Generally as fast as the rest of the traffic.  Travelling faster or slower can be hazardous.

<<Is it worth 50 cents to save 3.5 minutes?>>

Sometimes.

One of the oft-overlooked facts about crowded freeways is that slowing down all traffic would increase the number of cars on the freeway at any given time.  This can increase congestion and actually lead to overall higher fuel consumption.

Answer 12

2500rpms =70 mph my car.

Answer 13

Dear Dan1981,

   I am forty-six years old.

   When I was younger, I would not be conscious of the speed limit., I would just drive forward making sure I didn't hit anything or anyone. And I would make sure there weren't any police around.

   Then about ten years ago, my children and I rode public transportation, because I couldn't afford a car. One day, the bus driver got off the bus because the back door wouldn't close properly....and when the door wouldn't close the bus wouldn't go forward. I guess she had been experiencing this all morning. My children and I had just gotten on the bus, where we lived and she had gone maybe to stops and figured she had had enough of that. I was by the front door when she decided to get off to close the back door.

  Well, the bus STARTED MOVING FORWARD! I being a passenger, on many occasions, smalled talked to the bus drivers, use to notice how they moved their feet on the pedals. Well, I got up and ran and got into the driver's seat to stop the bus. The bus came within inches of hitting people who were crossing the street. I got an award from the bus company. But, it scared me s...o....bad, that it got me to thinking.

  I enrolled in a truck driving school and have my commercial license.

It was probably one of the best decisions I have ever made. Why?

Since having my commercial license,  I am definitely a more responsible driver. And...you see mistakes other people make and cringe. It has also made me think about being more safe for my children when I drive.

  My seventeen year old has her license and my sixteen year old has his temps. I am able to tell them, in an intelligent way what they are doing and what can be the consequences of making bad choices, better since having my commercial license. I am more informed.

  I have more respect for being behind the wheel; consequently, I drive slower.

  Through maturing, I have learned that the place I wanted to get to will still be there whether I get two minutes earlier by driving fast or not. And, I've learned, but don't always practise, that if I want to get somewhere on time, leave that much earlier, maybe fifteen minutes earlier, so that I'm not rushing.

  Since I've gotten older, I have a more respect for life and value life as prsious more.

  And also, I'm a nurse and have taken care of people who are victims of motor vehicle accidents. It's not a pretty site. The quality their lives is just awful.

  Now days, I drive the speed limit or slower.

  I hope that I have answered your question throughly.

  Sincerely,

  The Dinosaur Lady

Answer 14

As fast as I want, and mainly cause I want to, if it ticks off gw nuts thats just a bonus.

Answer 15

usually about 5 mph over the speed limit, so i don't get run off the road

Answer 16

i fly

Answer 17

The speed limit on the highway in front of our farm is 65mph.  When there is traffic on it (major empoyer 40 miles down the road from us) we drive 65mph.  Safer to drive the speed limit, than get passed on this two lane highway.

Our Interstate speed limit is 75 mph.

I personally rarely leave the farm.  Usually no more than once a week, some times as little as once a month.

Hubby on the other hand has to drive to his job (he works on commercial wind turbines).  Whenever he has been able to he carpooled with a friend who lived nearby and worked up there for a while.  The friend has now moved and works at a wind turbine site 4 hours away.

So hubby discovered if he drove the back roads, which are 55 mph, the milage in the Jeep went from just under 15 mpg, to just over 20 mpg.  Hubby has ordered some parts, so he can boost the millage some-more.  

The snow will be melting soon, and then he will drive my Merc Sable, which gets 36mpg on the fhighway.  He will be testing it out on the back roads at 55 mph, to see what kind of millage it gets.

We'll be happy when we can switch to farming full time, and raise almost all the fuel we need.  We raise the fuel (rapeseed) for our trucks and tractors right now, but cannot afford to pay the whopping taxes to also use the fuel off farm.

~Garnet

Homesteading/Farming over 20 years

Answer 18

set my cruise control to what the limit is posted